1. Field of the Invention
In general, the present invention relates to plug devices that are used to temporarily obstruct the skim filter ports of swimming pools. More particularly, the present invention relates to plug devices that are used in the winter to prevent water from gathering and freezing in the skim filter ports of a swimming pool.
2. Prior Art Description
In-ground pools that are used for swimming typically have a filter system with filter intakes both at the bottom of the pool and at the surface of the pool. Filter intakes at the bottom of the pool filter out dirt and debris that sinks to the bottom of the pool. The filter intakes at the surface of the pool filter out dirt and debris that may float near or at the top of the pool. The filter intakes at the surface of the pool often take the form of a skim filter port.
A typical prior art skim filter port is shown in FIG. 1. Referring to FIG. 1, it can be seen that the skim filter port 10 has a horizontal opening 12 that is exposed to the water 14 within the pool 16. The water level in the pool 16 is kept at the same level as the horizontal opening 12. As such, any dirt near or at the surface of the water 14 can be drawn into the horizontal opening 12.
The horizontal opening 12 leads to a vertical well 20 that is formed in the pool deck 18, adjacent the pool 16. The pool's filters draw in water from the bottom of the vertical well 20. A filter basket 22 is placed in the vertical well 20. The filter basket 22 catches sticks, leaves and other large objects and prevents those objects from being drawn into the primary pool filters. The filter basket 22 can be removed from the top of the vertical well 20. The vertical well 20 has an open top 24. The open top 24 is covered by a removable lid 26. To access the filter basket 22, the lid 26 is removed and the filter basket 22 is lifted out of the open top 24 of the vertical well 20.
The bottom of the vertical well 20 is connected to a pipe intake port 28. The pipe intake port 28 leads to the primary filters of the pool 16. A plug assembly 30 is provided. The plug assembly has a threaded bolt 33, and elastomeric plug body 31 and a wing nut 32. The plug assembly 30 is used to temporarily obstruct the pipe intake port 28 when the primary filter of the pool 16 is removed or otherwise undergoing maintenance. This is done by inserting the plug assembly 30 into the pipe intake port 28. The wing nut 32 is then turned to compress and expand the elastomeric plug body 31. This seals the pipe intake port 28.
Many in-ground swimming pools are located in geographic areas that experience temperatures that are below freezing during the winter months. If the skim filter ports 10 are left unprotected during the winter months, any water in the skim filter ports 10 can freeze. As water freezes it expands. As such, the frozen water can crack the vertical well 20, the horizontal opening 12 and/or the pipe intake port 28.
In order to prepare a pool 16 for winter, many people attempt to winterize their pools by plugging the vertical well 20 of the skim filter port 10 with various objects. The most common objects are empty bottles and blocks of wood. The problem with such objects is that they do not neatly fit the shape of the vertical well 20. Consequently, rain water is capable of passing around the object and collecting at the bottom of the vertical well 20. As the water collects at the bottom of the vertical well 20, it can lift the buoyant bottle or wood block up out of the vertical well 20, therein allowing for the admittance of even more water. Soon enough water becomes present that can cause damage as it freezes.
In the prior art, devices have been designed to keep water out of a skim filter port. However, such devices tend to be custom shaped to a particular model of skim filter port. As such, they cannot be mass produced for any and all in-ground pools. Furthermore, such prior art devices tend to be difficult and complex to install. Often, such prior art devices extend out of the horizontal opening of a skim filter port. This could prevent a pool's cover from properly seating around the top of the pool. In addition, the prior art devices do not engage the bottom of the vertical well. In this manner, the prior art devices are susceptible to buoyant displacement as water collects at the bottom of the vertical wells. Such prior art devices are exemplified by U.S. Pat. No. 4,879,772 to Meloney, entitled, Device For Closing Off A Pool Skimmer.
A need therefore exists for a device that can prevent water from collecting in a skim filter port that is capable of fitting a wide variety of skim filter port models, is easy to install, and is immune to the problems of buoyant displacement. These needs are met by the present invention as described and claimed below.